body {
    font-family: Arial, sans-serif;
    background-color: #f0f0f0;
    margin: 0;
    padding: 20px;
}

.container {
    max-width: 400px;
    margin: 0 auto;
    background-color: #fff;
    padding: 20px;
    border-radius: 10px;
    box-shadow: 0 0 10px rgba(0, 0, 0, 0.1);
}

h1 {
    text-align: center;
    color: #333;
}

.todo-list {
    list-style-type: none;
    padding: 0;
}

.todo-list li {
    margin-bottom: 15px;
    line-height: 1.6;
    padding: 10px;
    background-color: #e5f1e5;
    border-radius: 10px;
    position: relative;
}

a.sub-item-link {
    margin-left: 10px;
    text-decoration: none;
}

.sub-item-link:link {
    color: blue;
}

.sub-item-link:visited {
    color: purple;
}

.sub-item-link:hover {
    color: red;
}

.sub-item-link:focus {
    outline: 2px solid blue;
    outline-offset: 2px;
}

.sub-item-link:active {
    color: green;
}

.sub-item {
    list-style-type: square;
}